RU2048608C1 - Method of threaded pieces safeguard against corrosion - Google Patents

Abstract

FIELD: greasing methods in ship mechanical engineering. SUBSTANCE: first layer of grease is applied on thread piece surface by the piece plunging in composition, that has following components, mass diesel fuel 85 -95; kerosene 5 -15, and held there for 10 s under temperature of 0 25 C. Then the piece is withdrawn from the grease, kept under open air for 20 -25 minutes under temperature of 0 25 C and after that they apply second layer of grease, composed of mixture of petroleum refining heavy fractions. Besides, mixture of bitumen and residual fuel oil is used as petroleum refining heavy fraction. Before application heavy fraction mixture is deluted with petrol. EFFECT: improved quality of safeguard against corrosion. 3 cl

Description

 The invention relates to a lubricating technique, and in particular to methods for protecting threaded joints from the effects of the external environment in general and marine engineering.

 A known method of protecting metal parts from the effects of the environment using preservative grease (Sinitsyn V. Century. Greases in the USSR. Assortment. Handbook. M. "Chemistry" 1979, S. 207-245).

 A known method of applying a threaded lubricant, for example, R-2, designed to facilitate the screwing of threaded joints (ibid., Pp. 238-245).

 However, all these methods of protecting threaded joints with said lubricants are very expensive. Lubricants themselves contain many components to expand the range of their use, have a low resource, and do not provide long-term protection of threaded joints from environmental influences. As a result, operating costs for lubrication and maintenance labor are rising. One of the reasons for the relatively short-term protective effect of the P-2 thread lubricant is its insufficient adhesion to the surface of the thread parts, especially in the presence of rust.

Threaded connections on ships are exposed to water, sea salt, solar radiation, wind erosion, dust and temperature changes largely from 30 to 70 ^C. Therefore, an important property of the lubricating material is its ability to withstand all the above influences and reliably protected from corrosion threaded countertops compounds.

 There is also a method of corrosion protection of metal products of any shape and size, adopted as a prototype, by applying a PVC grease, having working and conservation properties in the presence of sea water.

 The disadvantage of this method of protection is the fragility of the protective action, since the lubricant does not provide the required protective properties, reliability and durability of threaded connections when exposed to the external environment.

 The proposed method of protecting threaded joints from corrosion solves the problem of increasing the durability of the protective action of threaded lubricant during long-term operation of mechanisms in contact with sea and atmospheric moisture in the range of tropical and arctic temperatures, for example, vessels of unlimited navigation area. As in the prototype, the protection of threaded parts from corrosion is carried out by treating the working surfaces with grease.

The difference lies in the fact that the first layer of lubricant, consisting of the following components, wt. Diesel Kerosene 85-95 5-15 at 0-25 ^{° C} for 10 s, the item is removed from a lubricant is heated in air for 20-25 minutes at 0-25 ^{° C,} and then applying a second lubricant layer, consisting of a mixture of heavy oil distillation fractions.

 In addition, a mixture of bitumen and fuel oil is used as a heavy fraction of oil distillation, and before application, a mixture of heavy fractions of oil distillation is diluted with gasoline.

 Two-layer lubrication allows to increase the durability of the protective action of the threaded connection.

The effect of using a two-layer lubricant is that its first layer, consisting of simple radicals of oil distillation, penetrating through the corrosion layer, provides good adhesion to the metal being protected. After applying the second layer and screwing the compound between the first and second layers, a mutual molecular exchange occurs, in which the molecules of the latter penetrate the corrosion layer without additional pressure and temperature requirements. Single coat composition Superlinear monootgonov which are lubricants, condensed with soap (fatty acid salt), the penetration into the layer of corrosion can occur only under high pressure (about 200-500h10 ⁵ Pa) at a temperature of 80-100 ^C. The molecular exchange process occurs without external pressure, but creates penetration conditions similar to pressures up to 1000x10 ⁵ Pa and above. The second factor affecting the durability and reliability of the protective layer is to add fuel oil to the bitumen. Fuel oil contains a large number of radicals with free bonds, which are closed by free bonds of the surface of any solid. The magnitude of the activity of these bonds is greater than the hydrogen bonds of water, which allows fuel oil or compositions containing fuel oil to connect to the surface in the presence of moisture and water. This explains the resistance of the coating to moisture.

The method is as follows. The lubricant prepared by mixing the components at a temperature of 0-25 ^C. Diesel 90 ± 5% kerosene and 10 ± 5% dip threaded part for applying a first layer for at least 10 seconds. Item itself must also be cooled to a temperature below 0 ° ^C. Then the threaded part is extracted from the lubricant and is maintained in air at a temperature of 0-25 ^{° C} for at least 20 min, and the upper temperature (25 ^{° C)} is limited only by considerations of engineering safety, as well as fire and explosion safety.

 If these issues are resolved, the temperature at which the lubricant should be applied can be increased to the extent that irreversible transformations in the components included in the lubricant can occur. After exposure to air, the threaded part is covered with a second layer of lubricant, also prepared by simply mixing the components in an arbitrary order.

 The viscosity of the applied second layer of lubricant is in the range of 60-150 centistokes, which also provides the convenience of coating.

 Depending on the initial composition and ambient temperature, it may be necessary to dilute the second layer with gasoline before application, the proportion of which in the volume can range from 0-10% by volume.

 To solve the problem, the specification of the grades of components included in the lubricant is not of fundamental importance.

Developed CNIIMF bilayer threaded conserving lubricant withstands at least 10 screwing and screwing at temperatures up to ⁷⁰ ° C, and ensures the development of threaded connections for 8-10 years under exposure to sea water, elevated humidity.

 For the second layer, the ISA mastic of the Slantsevsky regeneration plant (Slantsy, Leningrad region) can be used with the addition of 20-30% fuel oil without dilution with gasoline, since the ISA mastic is diluted with toluene.

Claims (3)

 1. METHOD FOR PROTECTING THREADED PARTS FROM CORROSION, including treating the working surfaces with grease, characterized in that a layer of grease is applied by dipping the first threaded part, consisting of the following components, wt. Diesel 85 95
Kerosene 5 15
at 0 25 ^o C for 10 s, the part is removed from the lubricant, kept in air for 20 25 min at 0 25 ^o C, after which a second layer of grease is applied, consisting of a mixture of heavy oil distillation fractions.  2. The method according to claim 1, characterized in that as a heavy fraction of the distillation of oil using a mixture of bitumen and fuel oil.  3. The method according to claim 1 or 2, characterized in that the mixture of heavy oil distillation fractions is diluted with gasoline before application.